RISSOIDAE US 



34 to 1 inch in length. Shell thick, with 1 1 rows of neat, rounded, whit- 

 ish, evenly spaced beads on the last whorl. Columella grooved; umbilicus a 

 narrow, oblique slit. Color of outer shell ash-gray. Interior dark-tan. Oper- 

 culum paucispiral. One of the commonest West Indian littoral species, usu- 

 ally found well out of water on the rock cliffs. 



Genus Echininus Clench and Abbott 1942 

 Subgenus Tectininus Clench and Abbott 1942 



Echininus nodiilosus Pfeiffer False Prickly-winkle 



Plate i9h 



Southeast Florida and the West Indies. 



V2 to I inch in length. Base of shell squarish. Whorls with 2 spiral, 

 carinate rows of sharp nodules in addition to 2 or 3 rows of smaller, blunt 

 nodules. Columella not shelved. Color grayish brown. Operculum multi- 

 spiral. Lives well above high-tide mark on rocky shores. Be sure not to 

 confuse with Nodilittorina tuberciilata whose beads are lined up axially one 

 under the other. 



Superfamily RISSOACEA 



Family RISSOIDAE 



Genus Cingula Fleming 1828 



Extremely small shells, conic-ovate; aperture round, peristome complete; 

 whorls moderately rounded. Nuclear whorls smooth. Umbilicus slit-like. 

 There are about 1 5 confusing species on the west coast of America, most of 

 which are found in Alaskan waters. 



Cingula montereyensis Bartsch Monterey Cingula 



Moss Beach to Monterey, CaHfornia. 



4 mm. in length, light-brown, smooth. Suture slightly indented. Un- 

 common from shore to 15 fathoms. 



Subgenus Nodulus Monterosato 1878 

 Cingula kelseyi Bartsch Kelsey's Cingula 



San Diego to Lower California. 



2 mm. in length, translucent-white, with microscopic spiral striations and 

 fine lines of growth. There are 4 other species in this subgenus which are 

 found in Alaska (C. asser Bartsch, C. kyskensis Bartsch, C. palmeri Dall and 

 C. cerinella Dall). 



